土霉素污染有机肥对土壤细菌多样性和结构的影响

Effects of oxytetracycline contaminated organic fertilizer on soil bacterial diversity and structure

土霉素作为养殖业中常用的一种促生长抗生素,极易在畜禽粪便中残留,直接还田可能对土壤微生物繁殖和作物生长带来潜在威胁。然而,现有研究多集中在高浓度梯度下,未能完全适用于实际生产情况,有必要研究土霉素在实际残留量下对细菌群落多样性的影响,为有机肥的安全施用提供理论依据。本研究设置土霉素添加量0.2 mg/kg,利用高通量测序技术分析细菌群落组成、结构变化和显著富集物种类型。结果表明,随时间推移土霉素显著改变了细菌群落结构,使厚壁菌门、放线菌门的相对丰度增加,增加幅度为1.1%~5.0%;同时,使变形菌门、绿湾菌门和拟杆菌门的相对丰度降低,降低幅度在2.0%以下。与对照组(CK)相比,添加土霉素处理(OCK)中高温放线菌科细菌显著富集。本研究证明了0.2 mg/kg土霉素能改变土壤细菌群落物种相对丰度,导致群落结构差异,并且显著富集了高温放线菌。这为探寻对抗生素污染具有指示作用的微生物提供新思路,并为有机肥的安全施用提供科学依据。

Oxytetracycline,as a commonly used growth-promoting antibiotic in the livestock breeding industry,is prone to residue in the manure,which poses a potential threat to the reproduction of soil microorganisms and crop growth when returned to the field.Most previous studies have set high concentration gradients,resulting in their limited application.Based on this,this article proposes to study the impact of actual antibiotic residues on bacterial community diversity to provide a theoretical basis for the safe application of organic fertilizers.In this study,the addition of oxytetracycline was set at 0.2 mg/kg,and high-throughput sequencing technology was employed to analyze bacterial community composition,structural changes,and types of significant enriched species.The results showed that the addition of oxytetracycline increased the relative abundance of Firmicutes and Actinobacteria,with a range from 1.1%to 5.0%;it also reduced the relative abundance of Proteobacteria,Chloroflexi,and Bacteroidetes,with a range below 2.0%.Compared to the control group(CK),Thermoactinomycetaceae were significantly enriched in the oxytetracycline group(OCK).Over time,oxytetracycline changed the structure of the bacterial community.This study proved that 0.2 mg/kg oxytetracycline can alter the relative abundance of soil bacterial communities and cause differences in community structure,leading to significant enrichment of Thermoactinomycetaceae in soil.Therefore,this study can provide inspiration for finding microorganisms that are effective against antibiotic pollution and lay the foundation for the safe application of organic fertilizers.